feat: add support for read in edge environments

[vnphanquang]

closes #12446
closes #11674

This PR helps with the cloudflare part of #12446. Added a test case and I also tested in a project bootstrapped with create cloudflare@latest. Hope i didn't miss anything 🤞.

Thanks all.

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🦋 Changeset detected

Latest commit: f93ad3d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@sveltejs/adapter-netlify	Major
@sveltejs/adapter-vercel	Major
@sveltejs/adapter-cloudflare	Major
@sveltejs/kit	Minor

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Preview: https://svelte-dev-git-preview-kit-13859-svelte.vercel.app/

[vnphanquang]

Not sure why that particular firefox CI test failed but it did pass on my local machine (pnpm test:cross-platform:build). Let me know, thanks!

[eltigerchino]

Thanks for this PR! Is there any chance you could continue the work from #11674 so that it's implemented in the Netlify and Vercel adapters too? I think if the reusable fetchFile function could allow passing a fetch function to it, we could pass env.ASSETS.fetch in the case of the Cloudflare adapter and it would just work.

Not sure why that particular firefox CI test failed but it did pass on my local machine (pnpm test:cross-platform:build). Let me know, thanks!

I re-ran the test in CI and it passes. Probably just a flaky test that failed.

[vnphanquang]

Ah yes. Sorry I missed Rich's PR in my search. Will look into it. Thanks for the input!

[vnphanquang]

@eltigerchino extracted into a streamFileContent function via 6da55ed. A couple of things:

• added some unit tests; I don't think they are strictly necessary but nice to have anyway,
• exported this util via @sveltejs/kit/adapter, as I think kit is already a peer-dependency for all adapters anyway,
• settled with this name rather than fetchFile since I feel like fetch would indicate a returned Response.

Also, I haven't added read for netlify & vercel yet, since edge environment can't be easily tested locally for them as far as I know (vercel requires connecting to a cloud project, and netlify docs says edge functions don't work locally).

I can spawn up some projects in netlify & vercel and do some manual tests, but I feel like i shouldn't block progress here. How about I do that in a separate PR?

Thanks

[eltigerchino]

Thank you!

Also, I haven't added read for netlify & vercel yet, since edge environment can't be easily tested locally for them as far as I know (vercel requires connecting to a cloud project, and netlify docs says edge functions don't work locally).

I can spawn up some projects in netlify & vercel and do some manual tests, but I feel like i shouldn't block progress here. How about I do that in a separate PR?

Yeah, manual testing for those are fine. There is no local environment for Vercel and like you said, Netlify's edge doesn't work locally.

[vladshcherbin]

Can this be prioritized? It's very cumbersome to use static assets with Cloudflare with unexpected outcome. Vercel and other can be added later

[eltigerchino]

I've added support to the Netlify and Vercel adapters. Also added a test suite for Netlify now that the local dev environment supports edge functions.

[vnphanquang]

I've added support to the Netlify and Vercel adapters. Also added a test suite for Netlify now that the local dev environment supports edge functions.

Thanks @eltigerchino. Apologies I couldn't find time to follow through with Netlify & Vercel. Appreciate you taking on the responsibility!

[dominikg]

is there a nicer way to handle clearing files? ideally the rollup call would take care of it if files is part of it?

[eltigerchino]

We currently do this for adapter-netlify, adapter-node, and adapter-vercel. Would it be a good soution to add a simple plugin such as below?

/**
 * @param {string} filepath
 * @returns {import('rollup').Plugin}
 */
function clearOutput(filepath) {
	return {
		name: 'clear-output',
		buildStart: {
			order: 'pre',
			sequential: true,
			handler() {
				rmSync(filepath, { recursive: true, force: true });
			}
		}
	};
}

[dominikg]

see above.